HTLV-1, like HIV-1, infects T lymphocytes, but unlike HIV-1, which rapidly kills infected T cells, HTLV-1 Tax activates cellular survival and proliferative pathways that instead induce T-cell proliferation, eventually leading, in a minority of infected patients, to an aggressive cancer called adult T-cell leukemia (34, 40). The gene discussed is CNTN2; the disease is adult T-cell leukemia/lymphoma.